Malignant gastric lymphoma is an uncommon but important lesion with a more favorable prognosis than that of gastric carcinoma. A total of 16 cases of gastric malignant lymphoma examined during a period from January 1980 to September 1983 at Seoul National University Hospital were subjected to the radiological and pathologic correlations. In all cases, the diagnosis was established by histopathology of the resected specimens (9 cases) or endoscopic biopsy specimens (7 cases). Based on the comparative stuty of upper G-1 series and macroscopic findings of the surgically resected specimen, the authors investigated the reliable radiographic findings which can be valuable in differentiation of gastric lymphoma from other gastric lesions, especially carcinoma, and suggested the following diagnostic criteria for the malignant lymphoma of the stomach. 1. Discrete multiple polypoid lesions with or without central umbilication. 2. Geographic ulcer, deviated form center of the mass. 3. Irregular thickness of elevated rim of the mass. 4. Diffuse giant gastric rugae. 5. Giant gastric rugae, mixed with other lesion. 6. Less desmoplastic response of the mass with persisting peristalsis. 7. Continuous spread into the duodenum.